Provide a way to shutdown the servers using an exit status.

src/ThreadedAsync/LoopCallback.py

@@ -25,7 +25,7 @@ register_loop_callback() to register interest.  When the mainloop
 thread calls loop(), each registered callback will be called with the
 socket map as its first argument.
 """
-__version__ = '$Revision: 1.12 $'[11:-2]
+__version__ = '$Revision: 1.13 $'[11:-2]
 
 import asyncore
 import select
@@ -150,6 +150,9 @@ def loop(timeout=30.0, use_poll=0, map=None):
     except that it also triggers ThreadedAsync callback functions
     before starting the loop.
     """
+    global exit_status
+    exit_status = None
+
     if use_poll:
         if hasattr(select, 'poll'):
             poll_fun = asyncore.poll3
@@ -162,7 +165,7 @@ def loop(timeout=30.0, use_poll=0, map=None):
         map = asyncore.socket_map
 
     _start_loop(map)
-    while map:
+    while map and exit_status is None:
         poll_fun(timeout, map)
     _stop_loop()